Gamma camera device and collimator

Abstract

A gamma camera device comprises a collimator with pinholes, the collimator enclosing an object space for receiving an object; a detector surface for detecting gamma radiation emitted by the object and passing through the pinholes of the collimator; and a controller for processing detector signals into an image of the object. The collimator and the object space have a common longitudinal axis, wherein the collimator comprises a plurality of groups, each of a plurality of pinholes having a center line. In each group, the pinholes are located in a plane perpendicular to the longitudinal axis, wherein the pinholes of the group together see a focal volume, the focal volume having a geometric center. Within each group, upon rotation around the longitudinal axis, the respective center line of each of the pinholes becomes coincident with the center line of each of the other pinholes of the group.

Description

Technical Field

[0001] The present invention relates to a gamma camera apparatus for generating an image of an object by means of gamma radiation, comprising: a collimator having pinholes surrounding an object space for receiving the object; a detection device having at least one detector having a detector surface for detecting gamma radiation emitted by the object and passing through the pinholes of the collimator as a detector signal; and a controller configured to process the detector signal into the image of the object, wherein the collimator and the object space have a common longitudinal axis, wherein the collimator comprises a plurality of groups, each of the plurality of pinholes having a centerline, wherein for each of the groups, the pinholes are located in a plane perpendicular to the longitudinal axis, wherein the pinholes of the group together see a focusing body having a geometric center. Background Technology

[0002] Such gamma camera devices are known in the prior art. MILabs sells the VECTor system, a gamma camera with a collimator having what is known as a "clustered pinhole," also described in EP 2073039.

[0003] A known drawback of the system is that the images obtained are not always clear, especially for higher photon energies, and / or it is not easy to obtain sufficient angular information about the object to be imaged. Summary of the Invention

[0004] The object of the present invention is to improve known devices to increase clarity, particularly for higher photon energies, and / or to make it easier to obtain sufficient angular information.

[0005] The present invention utilizes the gamma camera device according to claim 1 to partially achieve one or more of these objectives in any case.

[0006] Not limited to one interpretation, this configuration avoids or reduces the effect perceived by known gamma camera devices, namely, radiation penetrating the collimator at the location of the pinholes in a cluster of pinholes or a pinhole system. See, for example, the cited document EP 2073039. Figure 2 b, where, for example, the apex of the central portion 30 is susceptible to this penetration, thus causing a reduction in resolution. Furthermore, in EP 2073039, the distance between adjacent pinhole systems does not need to be large, because, for example, in... Figure 2At the bottom of b, the relatively far outward extension of the pinhole cone means that adjacent clusters must be arranged more separately than would be necessary on the other side (at the top of the figure). In this prior art, two or more pinholes, each only seeing a portion of the focusing body, are combined into a pinhole system or cluster that, as a whole, sees the entire focusing body. Each pinhole in the pinhole system has a centerline that forms an angle with the collimator surface at that point.

[0007] According to the invention, the pinholes in the cluster are actually separated from each other and arranged by "type" in a plane perpendicular to the longitudinal axis of the collimator. This measure makes the pinhole cones in the plane more (but not completely) parallel and less obstructive to each other. Thus, on average, there will be a greater distance between the pinhole cones, and there will be no sharp, thin areas as in EP 2073039, resulting in less penetration and resolution loss. Alternatively or additionally, they can be placed relatively closer together, making it easier to collect more, or in any case, sufficient, angular information about the object, such as the isotopic distribution within the object.

[0008] An alternative explanation is based on known tubular focusing pinhole collimators, such as those from the U-SPECT-I system, in which all pinholes (arranged in a ring, each located in a corresponding plane perpendicular to the collimator's longitudinal axis) point to a single point. All the pinholes of the collimator thus have overlapping fields of view, where the volume seen through all pinholes, or in any case through most of them, is represented as the focusing volume. Compared to a known gamma camera device with such a collimator, the present invention provides an improvement where all pinholes have a narrower field of view, for example, an image angle reaching at least 50% to, for example, 75% of the original image angle, and therefore less prone to penetration. However, the ring-arranged pinholes no longer all point to the same point, i.e., the center or geometric center of the focusing volume, but rather point eccentrically, i.e., to a theoretical circle around said point in a plane perpendicular to the collimator's longitudinal axis. Furthermore, for complete overlap, where the pinholes as a whole still see the same focal volume as before, the point does indeed need to fall within the field of view of each pinhole, but it is sufficient if the point is not located in the center line of that field of view or each field of view but closer to its edge. Now, to obtain the same focal volume, it is indeed necessary to combine multiple or all of the pinhole fields of view of each ring arrangement, but because the image angle of each pinhole is smaller, more pinholes can be placed in each ring arrangement, for example, in the collimator.

[0009] In this application, the centerline means the line of maximum transmission. This is often, but not necessarily, the longitudinal axis or axis of symmetry of the pinhole. Furthermore, the phrase "pinhole lies in a plane" means that each of the pinholes (with its apex or smallest cross-sectional portion, i.e., the "actual" pinhole) lies in a plane. The field of view is the spatial portion imaged onto the detector via the pinhole. The geometric center of the field of view is the geometric center of a homogeneous body with a focusing volume profile.

[0010] It is noted here that, for reasons related to imaging technology, it is useful, but not necessary, for the geometric center of the focusing volume to be located within the image angle of a single pinhole. The degree to which the centerline of the pinhole is tilted relative to the longitudinal axis of the object space / collimator is chosen accordingly. This ensures that, in each group, the field of view of the pinhole forms a continuous closed volume, and the focusing volume forms a portion of that volume. The focusing volume can be considered as a portion of the space seen through at least one pinhole in each group.

[0011] It will also be clear that the advantages of clustered pinholes cited in the prior art, namely their usefulness for higher photon energies due to the smaller required aperture angle of the pinhole, also apply to the present invention. Therefore, for further description of the advantages of the present invention, reference is made to paragraphs 11 and 26 of EP 2073039 B1.

[0012] The explanations and descriptions given above will be further clarified in the accompanying drawings and their description. Furthermore, specific embodiments of the invention are described in the dependent claims and the following portions of the introduction to the specification.

[0013] In a practical embodiment, each pinhole is configured as a channel with an invariant shape in the wall of the collimator.

[0014] In practical embodiments, all the pinholes of the collimator are arranged in a fixed order relative to each other. For example, all the pinholes are configured as channels of invariant shape in the walls of the collimator, such as in physical rings that form one or more rings of the collimator when stacked.

[0015] In some embodiments, when viewed from the respective pinholes, the corresponding center lines of the first group of the group pass through the geometric center from its right side in each case, and when viewed from the respective pinholes, the corresponding center lines of the second group of the group pass through the geometric center from its left side in each case. The terms "passing from the right side" or "passing from the left side" here mean, when viewed from the relevant pinholes, that the corresponding center lines extend to the right or left along the geometric center of the focusing body, thus keeping the geometric center on the left or right side. This can be advantageous for reasons of symmetry in reconstructing the recorded image as an isotopic distribution.

[0016] In a particular embodiment, the gamma camera device includes multiple first groups and / or multiple second groups. This creates the possibility of collecting image information from more different directions, i.e., because the different groups are located at different distances along the longitudinal direction. Advantageously, the number of the first groups differs from the number of the second groups by a maximum of 1, and more advantageously, the two numbers are equal. This allows for a mathematically simpler collimator structure, such as where the first and second groups are arranged mirror-symmetrically in a plane perpendicular to the longitudinal axis and passing through the geometric center of the focusing body. However, other arrangements are also possible.

[0017] In some embodiments, when viewed in the longitudinal direction, the first and second groups alternate with each other. In other words, a second group is always arranged between each pair of first groups, and vice versa. This achieves the following advantage. Because all the pinholes in a group are tilted towards the object to some extent, the image distances from one edge to another vary relatively greatly in one direction. To compensate for this, it is advantageous if the pinholes in the next group are tilted towards another edge, so that the portion of the image initially furthest from the pinholes in one group is now closest to the corresponding pinhole in the next group.

[0018] In some embodiments, one or each centerline of the first group and one or each centerline of the second group pass through the geometric center at a distance not equal to zero. Indeed, the pinholes of the first group and the associated pinholes of the second group form a cluster, as known from EP 2073039 itself, but because they are physically far apart in these embodiments of the invention, much less penetration occurs. As stated above, preferably, the geometric center of the focusing body always forms part of the field of view of the individual pinholes.

[0019] Specifically, the distances are different for at least two of the first group and / or at least two of the second group. Therefore, it is possible to provide even smaller image angles for pinholes in the first or second group, and thus make them less susceptible to penetration, while still imaging the focusing body by means of all pinholes in the first or second group. Here, the first portion of the pinhole has a centerline at a smaller distance from the geometric center, and this first portion "sees" the innermost part of the focusing body, while the second portion of the pinhole passes at a larger distance from the geometric center and sees the outermost part of the focusing body. Moreover, this can be extended to a larger number and different distances. Thus, this is a clear exception to the above statement that each pinhole field of view preferably includes the geometric center. This embodiment corresponds in principle to the n×n clustered pinholes of EP 2073039, where n≥3, and the focusing body also consists of more than two fields of view.

[0020] These embodiments can also be considered as each including a "fanning out" of the pinhole field of view, wherein the corresponding centerline of the pinhole forms a different angle with the corresponding line of association from the pinhole to the geometric center, such that different fields of view pointing at different angles always together image the focusing volume onto the detector. Note here that the pinholes on the ring at different distances also form different angles.

[0021] In some embodiments, at least one of the groups, and advantageously each, is rotationally symmetrical about the longitudinal axis, i.e., by placing the pinholes in each group in a uniformly distributed 360° pattern. While not strictly necessary, this allows for as many pinholes as possible in each group as possible with a predetermined minimum distance between them. The latter serves to prevent penetration. In particular, these embodiments make it possible to have more pinholes per group and overall than in the prior art, thereby correspondingly increasing radiation sensitivity.

[0022] In some embodiments, the collimator includes one or more annular collimator portions, each annular collimator portion having one or more of the groups. Thus, the collimator may include a physical ring of a single collimator material provided with all the pinhole groups, or two or more physical rings of collimator material (known as partial rings), each having one or more groups.

[0023] If needed, the collimator can be constructed in a modular manner. Note that the term "ring" here means not only a circular or cylindrical ring, but also any other closed loop, such as a triangle or other polygon, such as, for example, a hexagon, an octagon, etc. Furthermore, the physical ring of the collimator material, or each physical ring itself, can consist of two or more parts. Thus, a ring can be composed of two semi-cylinders, or of x straight plate sections forming an x-sided polygon, etc.

[0024] In some embodiments, the gamma camera apparatus further includes an additional pinhole group, preferably exactly one additional pinhole group, whose respective centerlines intersect the geometric center of the focusing body. For symmetry, this additional group is preferably located in a plane perpendicular to the longitudinal axis passing through the geometric center. In particular, the centerlines are all located in a plane perpendicular to the longitudinal axis. It should be noted that this additional group is not included in any alternating first and second groups along the longitudinal direction of the collimator. However, in the sense of the invention, it is also possible to configure these pinholes not to point towards the longitudinal axis (in this case, the geometric center), but rather eccentrically, i.e., the centerlines of the additional pinhole group pass through the longitudinal axis at a distance from it. These pinholes can collectively still always image the focusing body, but individual pinholes have a smaller image angle than necessary to see the entire focusing body itself.

[0025] The present invention also relates to a collimator for imaging an object using a gamma camera device equipped with the collimator by means of gamma radiation emitted by an object (e.g., a small animal or a part thereof). The collimator has pinholes and extends around an object space for receiving the object. The gamma camera device is provided with a detection device having at least one detector having a detector surface for detecting gamma radiation emitted by the object and passing through the pinhole of the collimator as a detector signal. The controller is configured to process the detector signal into said image of the object. The collimator and the object space have a common longitudinal axis having a longitudinal direction. The collimator comprises multiple groups, each of the multiple pinholes having a centerline. For each of the groups, the pinholes are located in a plane perpendicular to the longitudinal axis. The pinholes of the groups together see a focusing body having a geometric center. In each of the groups, the corresponding centerline of each of the pinholes passes through the longitudinal axis at a distance from it. In each of the group, when rotated about the longitudinal axis, the corresponding centerline of each of the pinholes becomes aligned with the centerline of each of the other pinholes in the group.

[0026] The collimator may also include one or more details and options as described herein.

[0027] The present invention also relates to a method for imaging an object using a gamma camera device and / or collimator as described herein by means of gamma radiation emitted by the object (e.g., a small animal or a part thereof). Attached Figure Description

[0028] The invention will now be explained in more detail with reference to the accompanying drawings, which illustrate some non-limiting exemplary embodiments, wherein the drawings show:

[0029] Figure 1 A perspective view of the gamma camera device according to the present invention is shown schematically.

[0030] Figure 2 A schematic cross-sectional view of a portion of a collimator 4' according to the prior art, particularly according to EP 2073039, is shown.

[0031] Figure 3 A schematic cross-sectional view of a portion of a comparable collimator 4'' is shown.

[0032] Figure 4 A partial open side view schematically showing a portion of the collimator 4' of the gamma camera apparatus according to the present invention is shown.

[0033] Figure 5 A schematic side view of the collimator 4'' as viewed along the longitudinal direction is shown, and

[0034] Figure 6 A side view of the collimator 4''' is schematically shown. Detailed Implementation

[0035] Figure 1 A perspective view of a gamma camera device according to the present invention is shown schematically. The gamma camera device is generally indicated by reference numeral 1. The device includes a housing 2 in which a detector 3 is arranged, a collimator 4 having a longitudinal axis 5, and a controller 6 having image processing functions connected to the detector 3.

[0036] Collimator 4 surrounds the space 7 of the object.

[0037] In this example, the collimator includes a first set of pinholes 8 and a second set of pinholes 9.

[0038] The gamma camera device 1 shown here has a triangular housing 2, as is known from the first U-SPECT by MILabs, but other housing shapes such as quadrilaterals or circles are also possible.

[0039] For clarity, in Figure 1 The third detector 3 has been omitted. The detector 3 is triangular in construction, which is an advantageous embodiment, for example, in combination with a collimator with a circular cross-section.

[0040] The outer casing 2 is made of, for example, lead or another material, in order to resist the deflection of gamma radiation into the environment as much as possible, unless this is technically unnecessary.

[0041] It should be noted that, for clarity, the gamma camera device 1 is not shown to scale in the accompanying drawings, and in fact, in order to obtain suitable image standards, the collimator 4 can be much smaller than the housing 2 with the detector 3.

[0042] Some detectors 3 are arranged inside the housing 2, where the detectors are against the wall, and under the influence of incident gamma radiation, the detectors emit electrical signals, which can be received and processed by the controller 6. The controller 6 can process the signals into an image of an object placed in the object space 7. The object is, for example, an animal (e.g., a small animal used for biological or pharmaceutical research), or a person or part thereof, which has been given a certain dose of a gamma-active substance. The animal or person therefore emits gamma radiation. In order to obtain a spatially resolvable image, it is necessary to use an imaging mechanism. In the case of gamma radiation, this is a pinhole (which is known in itself), here in the form of a collimator 4 having a first set of pinholes 8 and a second set of pinholes 9.

[0043] The collimator 4 is made of, for example, lead or tungsten, and may be a single physical ring or a combination of multiple rings axially attached to each other.

[0044] Two sets of pinholes 8 and 9 are manufactured as a ring or ring arrangement of pinholes, which are placed in a plane perpendicular to the common longitudinal axis 5 of the object space 7 and the collimator 4. It should be noted that more than two sets of pinholes can be provided.

[0045] It is also noted here that, for clarity, some components have been omitted, such as, for example, an object carrier, such as a plate on which the object to be inspected is placed, and possible displacement devices for moving the object carrier with the object in the object space 7, for example, for introducing the object into the object space at one end and removing the object from the object space.

[0046] It is also noted herein that, as is known per se, frame plates or partitions may be provided to limit the pinhole image on the detector to prevent overlap, shielding, etc., at the beginning and end of the object space. These components do not constitute part of the invention itself, and details regarding these components can be readily provided by those skilled in the art.

[0047] Now, referring to groups 8 and 9, please refer to the examples shown. Figures 2 to 6 The function of the present invention will be explained in more detail.

[0048] Figure 2 A schematic cross-section of a portion of a collimator 4' according to the prior art, particularly according to EP 2073039, is shown. This illustration shows two clusters 10'-1 and 10'-2, each of two pinholes 11'-1 and 11'-2 having a field of view 12'-1 and a centerline 13'-1, and a field of view 12'-2 and a centerline 13'-2, respectively. Field of view 12'-1 has an image angle α1, and field of view 12'-2 has an image angle α2. The common image angle of the pinholes in a cluster is α. Reference numeral 14' denotes the easily penetrated tip of the collimator where the pinholes are close together. It is noted here that, for clarity, only one of the field of view and centerline is shown for each pinhole, but all pinholes have both a corresponding field of view and a corresponding centerline. It is also noted that in this prior art, in practice, combined with magnified imaging on the detector, the distance between clusters is greater.

[0049] The collimator 4' is shown here as an example of a flat plate, which is one possibility. Nevertheless, in the context of this invention, collimators with a circular or circular cross-section have advantages in imaging on the detector surface.

[0050] Here, the collimator 4' has two clusters 10'-1 and 10'-2 as shown, with both pinholes together viewing the image angle α, while pinholes 11'-1 and 11'-2 each view a field of view with half an angle α1 or α2. Initially, this makes the "knife edge" of the pinhole, i.e., the narrowest part or the actual pinhole, more difficult or more resistant to the penetration of gamma radiation.

[0051] However, due to the different inclinations of the centerlines of the pinholes in the cluster, the distance between the clusters (i.e., Figure 2 d) is relatively large. Therefore, this limits the maximum number of pinhole clusters in a collimator of a given length, and thus also limits the radiometric sensitivity of the gamma camera system. Additionally, some blurring may occur at point 14 between pinholes 11'-1 and 11'-2 in a cluster. To prevent this, the individual pinholes in the cluster can be moved more spaced out, but this further reduces the maximum pinhole density in the collimator.

[0052] Figure 3 A portion of the collimator 4'' is shown in a schematic cross-sectional view, now featuring four pinholes 11'', each with an image angle α1 and a centerline 13''. The pinholes 11'' are positioned here with a slightly larger mutual spacing d'' than necessary, and there are no cones or similar features. Therefore, the degree of blurring due to penetration is less compared to that in the collimator 4'. Clearly, the maximum achievable pinhole density is significantly greater than in the prior art.

[0053] It should be noted that each of the pinholes 11'' shown only shows Figure 2 The pinholes 11''-1 and 11''-2 together represent "half" of the field of view. This can be compensated for in various ways.

[0054] First, in practice, such as Figure 1 As can be seen, a circular annular collimator is often used, in which pinholes 11'', also arranged in a ring, image ("see") the entire focus volume. Alternatively or additionally, this is compensated for by providing a second set of pinholes in the figure with a centerline symmetrically arranged in the vertical direction. Thus, in practice, Figure 2 The way each cluster 10' in the prior art is separated differs from placing the separated pinholes as close together as possible. It should be noted that if the second group of pinholes 11'-2 is also arranged in a ring, then they again appear as a single focusing body. For this reason, the second group of pinholes (which are always located at different positions relative to the focusing body) must also be placed at an angle relative to the transverse plane (the plane perpendicular to the longitudinal axis). This means that the average direction of the centerline of pinholes 11'-2, and also the centerline of the first group of pinholes 11'-1, points towards the geometric center of the focusing body.

[0055] like Figure 3As shown, pinholes 11'-1 oriented in the same direction are placed in one group, and other pinholes 11'-2 oriented in the same direction are placed in another group (not shown here). Together, these two groups provide approximately the same angular information as groups of clusters in the prior art, but with greater density due to the greater pinhole density, yet with less ambiguity.

[0056] In fact, this invention utilizes the discovery that it is not necessary to place a cluster of pinholes directly adjacent to each other, but rather they can be arranged differently. As mentioned above, the advantage is that a greater pinhole density and less blurring can be obtained. However, it should be noted that in the flat collimator shown, the achievable pinhole density is limited by preventing overlap on the detector, unless a maximum value of 1x is desired. However, in the tubular collimator, pinhole density plays a greater role because the field of view extends in the direction of the detector, thus providing more space for placing the pinholes closer together.

[0057] Figure 4 A schematic side view is shown, partially through a portion of the collimator 4' in the gamma camera apparatus according to the invention. This includes a first set of pinholes 8' and a second set of pinholes 9'. All pinholes in the figure extend inward to the right, such that the focusing body (not shown here), i.e., the volume ultimately visible through all the sets of pinholes, is also located on the right side. It is important to note that both sets 8' and 9' are located on one side of the focusing body. This provides the advantage that distortion in one set, caused by the average distance at one edge of the field of view through the pinholes from the focusing body to the detector being greater than the average distance at the opposite edge of the field of view, can be compensated for, because the distortion caused by the average distance at the corresponding edge of the field of view through the other set of pinholes is exactly the opposite.

[0058] In the longitudinal direction of the collimator, the center lines passing through the first set of pinholes 8', as observed from the left, in each case pass through the longitudinal axis 5 at a distance to the right. This means that in Figure 4 The pinhole 8'-4, located in the middle above the collimator, points slightly downwards. Conversely, the corresponding centerlines of the second group of pinholes 9', viewed from the left along the longitudinal direction of the collimator, each pass through the longitudinal axis on the left. This means that the pinhole 9'-4, located in the middle above the collimator in the figure, points slightly upwards. Since the centerlines of the pinholes in a group can become congruent upon rotation, the orientation of each centerline is established as a function of position / angle on the collimator. For example, if the pinholes 8' are evenly distributed around the perimeter and number 16, then when rotated by 360 / 16 = 22.5° or a multiple thereof, the centerline of one pinhole 8' becomes congruent with the other centerline of another pinhole 8' in the same group.

[0059] Figure 5 A schematic cross-section through the collimator 4'' is shown as viewed in the longitudinal direction.

[0060] The collimator 4'' is tubular and has a radiation-shielding wall extending around the object space. Preferably, the tubular wall is cylindrical, wherein the object space and the collimator share a common longitudinal axis 5.

[0061] A pinhole is positioned on the wall of the collimator 4''. In a known manner, gamma radiation emitted by an object present in the object space passes through the pinhole and is incident on the detector (not shown in detail) of the gamma camera device.

[0062] For the sake of simplicity, Figure 5 Only four pinholes 8''-1 to 8''-4 of a set are shown, along with their centerlines 13''-1 to 13''-4 and the image angle / field of view α''-1 to α''-4. Again, 5 represents the longitudinal axis of the collimator 4'', and 15 represents the theoretical ring or cylinder around the longitudinal axis 5, to which the centerlines of all the pinholes in the set contact, and 16 represents the focusing body.

[0063] The following description is based on a pinhole 8''-1, which serves as an example for the other pinholes in the group. First, it should be noted that the centerlines of the pinholes in the group shown are all "slanted," meaning that they do not intersect the longitudinal axis 5, but pass through the longitudinal axis 5 at a distance to one side.

[0064] Figure 5 As illustrated in the pinhole group shown, when rotated about the longitudinal axis 5, the center line becomes aligned with the center line of each of the other pinholes in the group.

[0065] In order to limit Figure 5 The number of lines in the collimator has been chosen to allow one edge of the field of view to extend precisely through the middle of the collimator 4''. In practice, it is best to choose a slightly wider field of view (image angle α'') for each pinhole 8'' and allow the center lines to overlap.

[0066] Pinhole 8''-1 has a centerline 13''-1 and an image angle α''-1. The volume portion imaged by pinhole 8''-1 lies between the horizontal line in the diagram passing through the longitudinal axis 5 and the line extending obliquely upwards. This occupies approximately half of the entire focusing body 16. Moreover, it is compensated by the field of view α''-3 of the opposing pinhole 8''-3, such that pinholes 8''-1 and 8''-3, in principle, see the entire focusing body 16 together. This is further supplemented by another set of pinholes (not shown here) (preferably but not necessarily adjacently positioned) pointing precisely in another direction of the longitudinal axis 5. It is noted here that the focusing body 16 is represented here as a circle, whereas for a static collimator with four pinholes, it naturally has a diamond-like cross-section with a greater or lesser degree of circularity. However, the collimator can also be designed to rotate about the longitudinal axis 5, thereby averaging a fairly circular cross-section for the focusing body. Additionally, viewed from a cross-section transverse to the longitudinal axis 5, the focusing body 16 has a more circular shape as the number of pinholes increases.

[0067] exist Figure 5 In the example shown, this means that the pinholes in the adjacent group are located at the height of pinhole 8''-1, but have a field of view and center line that are symmetrically arranged on a horizontal line extending from pinhole 8''-1 to pinhole 8''-3 (more precisely: symmetrical in the plane formed by said line and longitudinal axis 5). It should be noted that this pinhole... Figure 5 The field of view of the adjacent pinhole α''-1 will actually be located at the same point as pinhole 8''-1 because it is always a side view along the longitudinal axis, and therefore more or less a projection on a plane perpendicular to the longitudinal axis. It should be understood that the field of view of the adjacent pinhole and the field of view α''-1 of pinhole 8''-1 actually together cover the entire focusing body, or the entire focusing body 16. Thus, these two pinholes actually together form a point that can be... Figure 2 The two pinholes 11'-1 and 11'-2 in cluster 10'-1 are equivalent to two pinholes.

[0068] Clearly, the complete total focusing volume can be considered as consisting of the volume portion seen through at least one of a set of pinholes. This readily ensures—and advantageously—that the same volume can also be seen through another set of pinholes, preferably pinholes from other sets.

[0069] Figure 6 A schematic side view of the collimator 4''' is shown. The collimator 4''' has a longitudinal axis 5''' and is composed of seven physical rings of collimator material 20-1 to 20-7, each ring having associated pinhole groups 21-1 to 21-7 arranged in a ring. For some pinholes, the channels passing through the associated rings are schematically depicted with dashed lines. All pinholes together sweep the focusing body 16'''.

[0070] Clearly, according to the invention, groups 21-1 and 21-7, 21-2 and 21-6, 21-3 and 21-5 each form a corresponding first and second group of pinholes, i.e., passing through the longitudinal axis 5''' in opposite directions. If ring 20-7 is symmetrically arranged in a plane perpendicular to the longitudinal axis 5''' and imaged on ring 20-1, then the pinholes of groups 21-1 and 21-7 are placed in one and the same ring, obtaining a cluster approximately the same as that according to the known EP 2073039. However, according to the invention, more pinholes may also be provided for each group 21, since it is not necessary to place them in this manner.

[0071] Also note that the central ring 20-4 has a set of pinholes 21-4, whose centerlines all point towards the longitudinal axis 5''', and are therefore different from the corresponding first and second sets of pinholes 21-1, 21-2, ... .... Nevertheless, these pinholes 21-4 are also preferably eccentrically oriented, i.e., their centerlines pass through the longitudinal axis 5 at a distance, and their centerlines are tangent to the theoretical circle or cylinder 15 surrounding the longitudinal axis 5, thus having the same advantages, such as a lower degree of blurring due to penetration.

[0072] All groups 21-1 to 21-7 together see the focusing body 16''', thus the collimator (and the associated gamma camera device) also possesses all the advantages of a focusing collimator, such as higher achievable radiometric sensitivity and resolution. According to the invention, each pinhole can therefore provide an image angle smaller than that necessary to see the entire focusing body 16''' individually, such as approximately half of it.

[0073] According to some embodiments, even a smaller field of view can be provided for each pinhole, such as Figure 6 In the case of the pinhole, it is approximately one-sixth or even one-eighth of the cross-section of the focusing body 16''' (in practice, slightly larger due to the desired overlap). Still, in order to be able to see the entire focusing body, it is desirable that the different rings also image different portions of the focusing body 16'''. As an example, the pinholes of rings 21-1 and 21-7 image the innermost third or quarter of the focusing body 16''' (in each case, by cross-section, not by volume), the pinholes of rings 21-2 and 21-6 image the next innermost third or quarter, the pinholes of rings 21-3 and 21-5 image the outermost third or the second outermost quarter, and the pinhole of ring 21-4 image any third or the outermost quarter of the focusing body 16'''. Moreover, different orders and configurations are also possible. It is important to note that the entire focusing body 16''' is always imaged, but the pinhole has a very small image angle, resulting in less blur.

[0074] Furthermore, the collimator is shown here as a stack of physical rings 20-1 to 20-7, for example, due to the desired modularity or easier production of the collimator 4'''. It should be explicitly noted that one or more or all of the rings can also be combined into a single collimator body.

[0075] The embodiments shown are purely illustrative of the invention and are not intended to limit the invention in any way. However, the scope of protection is determined by the appended claims.

Claims

1. A gamma camera device (1) for generating an image of an object by means of gamma radiation, said gamma camera device (1) comprising: - Collimator with pinhole (4; 4'； 4''； 4'''), the collimator extends around the object space (7) for receiving the object, - A detection device having at least one detector (3), the detector (3) having a detector surface for detecting gamma radiation emitted by the object and passing through the pinhole of the collimator as a detector signal, and - Controller (6), the controller (6) being configured to process the detector signal into the image of the object, The collimator and the object space (7) share a common longitudinal axis (5), which has a longitudinal direction. The collimator comprises multiple groups, each of the multiple pinholes having a centerline (13; 13'; 13''). In each of the groups, the pinhole is located in a plane perpendicular to the longitudinal axis (5). The pinholes in the group together show a focusing body (16) having a geometric center. In each of the groups, the corresponding centerline of each of the pinholes passes through the longitudinal axis at a distance from the longitudinal axis, and when rotated about the longitudinal axis, the centerline becomes aligned with the centerline of each of the other pinholes in the group.

2. The gamma camera apparatus of claim 1, wherein for each pinhole in the first group of the group, when viewed from the corresponding pinhole, the corresponding centerline passes through the geometric center from the right side of the geometric center, and wherein for each pinhole in the second group of the group, when viewed from the corresponding pinhole, the corresponding centerline passes through the geometric center from the left side of the geometric center.

3. The gamma camera device according to claim 2, comprising a plurality of first groups and / or a plurality of second groups.

4. The gamma camera apparatus according to claim 3, wherein when viewed in the longitudinal direction, the first group and the second group alternate with each other.

5. The gamma camera device of claim 2, wherein the center line of one or each of the pinholes in the first group and the center line of one or each of the pinholes in the second group pass through the geometric center at a distance not equal to zero.

6. The gamma camera device of claim 3, wherein the center line of one or each of the pinholes in the first group and the center line of one or each of the pinholes in the second group pass through the geometric center at a distance not equal to zero, wherein the distance is different for at least two of the first group and / or for at least two of the second group.

7. The gamma camera apparatus of claim 1, wherein each of the groups is rotationally symmetrical about the longitudinal axis.

8. The gamma camera apparatus of claim 1, wherein the collimator comprises one or more annular collimator portions, each of the annular collimator portions having one or more of the groups.

9. The gamma camera apparatus of claim 1, further comprising a pinhole of an additional group, wherein the respective centerline of the pinhole of the additional group intersects the geometric center.

10. The gamma camera apparatus of claim 1, wherein the apparatus is configured to rotate the collimator about the longitudinal axis.

11. The gamma camera device of claim 1, further comprising exactly one additional set of pinholes, wherein the respective centerlines of the pinholes of the additional set intersect the geometric center and are all located in a plane perpendicular to the longitudinal axis.

12. A method for imaging an object using a gamma camera apparatus according to any one of claims 1 to 11 by means of gamma radiation emitted by the object.

Images